In the conventional brain diagnosis, X-ray imaging and brain wave measurement have been conducted as inspections that can be executed with relative ease.
From the 1980's on, a diagnosis for obtaining detailed information in an apparatus of a larger scale, using a positron emission tomography (PET) apparatus or a single photon emission CT (SPECT) apparatus capable of measuring and imaging the dynamics of a cerebral blood flow tracer administered in the brain or the metabolism of glucose in the brain with a gamma camera or a dedicated scanner has also spread, although the diagnosis needs a considerably large-scale apparatus.
As another method, there is also an optical topography apparatus for irradiating the head with a weak infrared light under the present conditions, and measuring the reflection intensity to measure and image the activity state of the cerebral cortex located inside of the skull, and thereby measure the activity situation in the brain.
In the case where an easy method, such as X-ray imaging or brain wave measurement, is used in the conventional brain diagnosis, it is possible to observe a lesion such as cerebral infarction or a tumor, or observe a serious state of a disease, such as the Alzheimer's disease, the Parkinson's disease or the new variant Creutzfeldt-Jakob disease commonly called bovine spongiform encephalopathy (mad cow disease). In this case, however, it is not possible to observe such a progressive disease in its initial state before subjective symptoms occur. When symptoms have appeared, medical measures are already impossible or extremely difficult in many cases. As for some of the above-described diseases, medical techniques for preventing the progress already exist. Nonetheless, it is seldom that such a disease is found in a situation of such a degree as not to interfere with a patient's daily life. In the existing circumstances, therefore, eventually the patient must continue to have a serious disturbance throughout their life.
If the PET, SPECT, optical topography apparatus, or the like is used, the above-described disease can be found before revelation of the symptoms of which the patient is conscious. However, these apparatuses are extremely large-scaled and expensive, and consequently they cannot be introduced into a medical examination such as a complete medical checkup as general inspection.
Nowadays, in situations where brain diseases such as the mad cow disease pose problems, it has been recognized that early finding of a disease occurring in the brain is extremely important to the welfare of mankind. Implementation of a technique and an apparatus for finding the initial state of the above-described diseases, which cannot be found by using a simple method such as X-ray imaging or brain wave measurement, without requiring a complicated large-scale apparatus such as the PET, SPECT, or the optical topography apparatus is wanted keenly.
The present invention has been achieved in order to solve the above-described problems. An object of the present invention is to provide an apparatus that evaluates and diagnoses the initial state and the progress state of a brain disease relatively easily and without applying unreasonable load on a human body.